This invention relates to injection moldable composites, and more particularly to electrically conductive, aluminum galvanic compatible, polyetheretherketone (PEEK) injecting moldable composites. PEEK resins are polyarylene ether ketones having a repeating unit of the formula: ##STR1##
In searching the prior art for PEEK compositions and structures having anti-static characteristics, the following patents were developed:
______________________________________ Patent Number Inventor(s) ______________________________________ 4,416,924 (U.S.) Peterson et al. 4,772,521 (U.S.) Kromrey 4,723,350 (U.S.) Kobayaski et al. 4,599,383 (U.S.) Satoj 4,735,828 (U.S.) Cogswell et al. 4,783,349 (U.S.) Cogswell et al. 2,129,523 (U.K.) Murray 0,102,159 (E.P.) Cogswell et al. 4,327,832 (U.S.) de Matteo 4,330,811 (U.S.) Bordner 4,770,838 (U.S.) Cattanach et al. 3,580,983 (U.S.) Jackson 3,555,170 (U.S.) Petzetakis 3,963,856 (U.S.) Carlson et al. 3,958,066 (U.S.) Imamura et al. 3,070,132 (U.S.) Sheridan 3,499,815 (U.S.) Hof 3,519,520 (U.S.) Newman, Jr. 3,070,871 (U.S.) Ryckebosch ______________________________________
As is known from the prior art, injection molded composites similar to PEEK, and including PEEK, are used in many areas and applications including in modern day aircraft. The composites are used to replace metal parts, and in many applications, on a one-to-one basis. The primary reasons for the use of composite materials are lighter weight, less sensitivity to corrosion, and in some cases lower costs. PEEK as a material has been used in many applications in the lay up form. In the injection molded form, however, there have been less applications because of various problems. For example, in the aircraft fuel area where PEEK must come into contact with fuel and aluminum, injection molded parts have not been used to date because the parts have not met aircraft requirements.
One of the past shortcomings of injection molded PEEK material was the incompatibility (galvanic) of PEEK filled with carbon when mounted against aluminum in a fuel system due to unsatisfactory corrosive results. Filling PEEK with glass as opposed to carbon has satisfied the galvanic corrosion problem, but not the conductivity problem, since valves and other components in the fuel area are generally required to dissipate static electricity buildup. Glass filled PEEK is basically an insulator and not a conductor, therefore, it cannot meet the electrical conductivity requirements. The carbon filled PEEK will meet the electrical conductivity requirement, but will not meet the galvanic corrosive requirements. These problems and conditions have been known for at least two years in the aircraft industry and a satisfactory solution had not been forth coming.
An injection moldable composite has been discovered which overcomes the aforementioned difficulties and enables development of a composite injection molded body which may be used in the fuel system, and can be mounted directly to aluminum. The body produced from the material will meet both the galvanic corrosion compatibility electrical conductivity required by the aircraft industry.